1. Field of the Invention
The present invention relates to an apparatus for analyzing gases such as oxygen (hereinafter referred to as "O"), nitrogen (hereinafter referred to as "N") and hydrogen (hereinafter referred to as "H") which are contained in metals.
2. Description of the Prior Art
The analysis of O, N and H contained in metals has conventionally been done by treating gaseous components such as carbon monoxide (CO), gaseous nitrogen (N.sub.2) and gaseous hydrogen (H.sub.2), which are generated from O, N and H which are respectively contained in a sample being analyzed, by heating the sample to about 3,000.degree. C. in a graphite crucible with inert gases which are contained therein and which serve as carrier gases. The gaseous components are then detected by means of a Thermal Conductivity Detector (TCD). However, this method involves and requires a two-stage measurement Specifically, the measurement of O and N is performed first and then, the measurement of H is performed. Helium (He) has been used as the carrier gas in the measurement of O and N, while argon (Ar) has been used as the carrier gas in the measurement of H. Such required two-stage measurement has been mentioned due to the fact that He is similar to H.sub.2 and Ar is similar to CO.sub.2, as well as to N.sub.2, with respect to their respective thermal conductivities at the same temperature when a Thermal Conductivity Detector (TCD) is used.
In practice, the measurement of O as well as N and H has been done as follows: